unix_io.c: Add #ifdef NO_IO_CACHE which disables all userspace

	caching by the unix_io layer.  Not enabled, only for
	debugging.

diff --git a/lib/ext2fs/ChangeLog b/lib/ext2fs/ChangeLog
index 7cce3faf57ae8fb15c2c9f1df1b884cc22064a26..5153d71f4fc74c2b812f10246e0ffeb1d131f5e7 100644 (file)
--- a/lib/ext2fs/ChangeLog
+++ b/lib/ext2fs/ChangeLog
@@ -1,3 +1,9 @@
+2003-05-13  Theodore Ts'o  <tytso@mit.edu>
+
+       * unix_io.c: Add #ifdef NO_IO_CACHE which disables all userspace
+               caching by the unix_io layer.  Not enabled, only for
+               debugging. 
+
 2003-05-05  Theodore Ts'o  <tytso@mit.edu>
 
        * test_io.c: Pay attention to the environment variables

diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c
index ae498da3da35b57b14fe1fd881903c4339db8e36..b2deb70ec646547188817f952cac0b3a0fe662da 100644 (file)
--- a/lib/ext2fs/unix_io.c
+++ b/lib/ext2fs/unix_io.c
@@ -278,6 +278,7 @@ static void free_cache(io_channel channel,
        }
 }
 
+#ifndef NO_IO_CACHE
 /*
  * Try to find a block in the cache.  If the block is not found, and
  * eldest is a non-zero pointer, then fill in eldest with the cache
@@ -358,6 +359,7 @@ static errcode_t flush_cached_blocks(io_channel channel,
        }
        return retval2;
 }
+#endif /* NO_IO_CACHE */
 
 static errcode_t unix_open(const char *name, int flags, io_channel *channel)
 {
@@ -471,7 +473,9 @@ static errcode_t unix_close(io_channel channel)
        if (--channel->refcount > 0)
                return 0;
 
+#ifndef NO_IO_CACHE
        retval = flush_cached_blocks(channel, data, 0);
+#endif
 
        if (close(data->dev) < 0)
                retval = errno;
@@ -494,8 +498,10 @@ static errcode_t unix_set_blksize(io_channel channel, int blksize)
        EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
 
        if (channel->block_size != blksize) {
+#ifndef NO_IO_CACHE
                if ((retval = flush_cached_blocks(channel, data, 0)))
                        return retval;
+#endif
                
                channel->block_size = blksize;
                free_cache(channel, data);
@@ -519,6 +525,9 @@ static errcode_t unix_read_blk(io_channel channel, unsigned long block,
        data = (struct unix_private_data *) channel->private_data;
        EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
 
+#ifdef NO_IO_CACHE
+       return raw_read_blk(channel, data, block, count, buf);
+#else
        /*
         * If we're doing an odd-sized read or a very large read,
         * flush out the cache and then do a direct read.
@@ -567,6 +576,7 @@ static errcode_t unix_read_blk(io_channel channel, unsigned long block,
                }
        }
        return 0;
+#endif /* NO_IO_CACHE */
 }
 
 static errcode_t unix_write_blk(io_channel channel, unsigned long block,
@@ -582,6 +592,9 @@ static errcode_t unix_write_blk(io_channel channel, unsigned long block,
        data = (struct unix_private_data *) channel->private_data;
        EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
 
+#ifdef NO_IO_CACHE
+       return raw_write_blk(channel, data, block, count, buf);
+#else  
        /*
         * If we're doing an odd-sized write or a very large write,
         * flush out the cache completely and then do a direct write.
@@ -615,6 +628,7 @@ static errcode_t unix_write_blk(io_channel channel, unsigned long block,
                cp += channel->block_size;
        }
        return retval;
+#endif /* NO_IO_CACHE */
 }
 
 static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
@@ -628,11 +642,13 @@ static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
        data = (struct unix_private_data *) channel->private_data;
        EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
 
+#ifndef NO_IO_CACHE
        /*
         * Flush out the cache completely
         */
        if ((retval = flush_cached_blocks(channel, data, 1)))
                return retval;
+#endif
 
        if (lseek(data->dev, offset, SEEK_SET) < 0)
                return errno;
@@ -656,7 +672,9 @@ static errcode_t unix_flush(io_channel channel)
        data = (struct unix_private_data *) channel->private_data;
        EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
 
+#ifndef NO_IO_CACHE
        retval = flush_cached_blocks(channel, data, 0);
+#endif
        fsync(data->dev);
        return retval;
 }